Preservation of Alveolar Ridge using Graft Material after Tooth Extraction: A Clinical Trial.

BACKGROUND: The alveolar process is a tooth-dependent structure, and hence, removal of teeth results in the alteration of alveolar process. To alter bone remodeling after dental extraction, various techniques have been put forward for ridge preservation. AIM: The aim of this study is to evaluate and compare the changes of hard and soft tissues in postextraction socket after the application of bone graft material.
MATERIALS AND METHODS: Healthy patients of sample size of 40 were selected who underwent the extraction of anterior tooth irrespective of the arch, from premolar of one side to another, with the exception of incisors in mandible. Twenty patients were randomly selected as the control group and other 20 as the experimental group using an allograft bone material, i.e., beta-tricalcium phosphate to fill the socket. Cone-beam computed tomography (CBCT) was done as baseline preoperative and postoperative at 14 weeks after the extraction. CBCTs data help in recording linear and volumetric measurements which was performed by calibrated examiners to record all the measurements. After measurements, digital planning of dental implants was performed.
RESULTS: Forty participants were selected, in which 20 patients each were as the experimental and control groups. No significant difference was found at basal line at any of the cases. At follow-up of 14 weeks, statistical significance was seen in buccal and lingual plate height in the experimental group, and no significant difference was seen in the control group.(P = 0.023).
CONCLUSIONS: This study clearly points out that an alveolar ridge preservation technique provides therapeutic benefit by limiting bone resorption in comparison to extraction alone. Copyright:

INTRODUCTION

The periodontium comprise of gingival tissues, cementum, PDL, cortical, and cancellous bone. However, an augmentation of the existing alveolar bone is often necessary to obtain excellent functional and esthetic restorations of the implants. Nowadays, several biocompatible materials and autogenous bone are used to treat bone atrophy of the alveolar ridges, thus allowing ideal implant placement.[1] Subsequent to tooth extraction, the alveolar ridge undergoes resorption and atrophy, which cause a wide range of dimensional changes among individual patients. 8–10 after tooth extraction soft- and hard-tissue healing was studied in humans and animals by histologic and clinical evaluations.[23] The healing of the extraction socket goes through the sequence of events, including the formation of a coagulum that was replaced with a provisional connective tissue matrix: After 1 month, woven bone filled the extraction socket, a cortical ridge, including woven and lamellar bone, was observed after 3 months; subsequently, the woven bone was gradually replaced with lamellar bone and marrow.[4]

Alveolar ridge preservation strategies were aimed to minimize the loss of ridge volume following tooth extraction and help to preserve buccal and lingual wall of the socket. In described method, immediately after extraction socket is filled with a biomaterial which helps in preserving ridge. This process is essential in cases where implant is planned.[5]

When extraction socket filled with the bone substitute is known as socket grafting. Nowadays, alveolar ridge preservation technique has become most popular. There are many publications regarding alveolar preservation technique.[67] Literature shows that alveolar ridge preservation is lacking data. Hence, the present randomized clinical trial was carried out to eliminate the curbs of antecedent literature work.

MATERIALS AND METHODS

The clinical component of the study was carried out on 40 patients were included who requires the extraction of maxillary incisors, canine and premolars or mandibular canine or premolar. Mandibular incisors were excluded. At clinical examination, all patients were explained in detail about the intention and duration of study. The patient ages from 18 to 65 years who require single tooth extraction were included in the study, and informed consent was obtained before study.

Exclusion criteria

If the patient was allergic or hypersensitive to any of material used in study or patient with hematological disorder, organ failure, any cancer, with habit history of smoking, and pregnant women were excluded from the study.

After initial screening, site-specific intra-oral pictures and X-ray were recorded. The patients were randomly assigned and divided into two groups. 20 as control group and 20 as experimental group for which allograft was used beta-tricalcium phosphate.

Just before extraction, a cone-beam computed tomography (CBCT) was obtained. All procedures were done under local anesthesia. Following extraction, integrity of alveolar wall was confirmed using unc-15 periodontal probe[Figure 1].

Figure 1

Atlas: (a) Pre-operative, (b) Intra-operative, (c) Post-operative

For control site, socket was left as it is to heal by natural phenomenon. After this, alveolar preservation procedure was done in the experimental group. Beta tricalcium phosphate was placed into the socket till the level of crystal bone. A horizontal suture was done to maintain the integrity of material.

At follow-up appointment of 1st week sutures was removed, and oral hygiene was reinforced. At 14th week post-operative visit: Before clinical assessment 2nd CBCT was repeated all final measurements were done and after recording alveolar ridge height patient were further appointed for the next treatment plan.

Frame of each CBCT scan was adjusted for the linear measurements for buccal and lingual cortical height in a cross-sectional frame. While for mesial and distal cortical height, measurements were done in a tangential frame. Moreover, vertical measurements were done from the most coronal aspect of cortical bone to the fixed anatomical point apically. Preoperative and postoperative values were calculated by the amount of crystal bone loss. Descriptive statistics were used for volumetric analysis and lineal and basal line measuring. Statistical significance level was kept at value of P at < 0.05. The values of mean and standard deviation were assessed, and difference between two groups was analyzed by Wilcoxon rank sum test.

RESULTS

A total of 40 participants were recruited for the study and were randomly distributed into two groups. Dimensional changes were calculated by comparing the CBCT scans taken immediately after grafting procedure 1st day and 14th week postoperatively.

Demographic variables are explained in Table 1. Basal line parameters are explained in Table 2.

Table 1

Demographic parameters of the study subjects

Demographic parameters	Group I (control)	Group II (graft)
Gender	Females - 9	Females - 13
	Males - 11	Males - 7
Age (in years)	55.37±9.88	59.42±12.11

Table 2

Clinical parameters at baseline (in millimeter [mm])

Parameters	Control group	Graft group
Mucosa (keratinized)	2.71±1.16	3.21±1.58
Thickness of the bone
At buccal aspect	0.51±0.20	0.88±0.24
At lingual aspect	1.00±0.25	0.77±0.13
Thickness of the gingiva	0.39±0.1	0.33±0.02
At Buccal aspect
At lingual aspect	0.73±0.22	0.74±0.25
Span of the alveolar ridge (Buccolingual)	8.16±1.3	8.26±1.23

Table 3 depicts the clinical measurements, and Table 4 showed volumetric changes of basal line to 14th week follow-up. Table 5 shows the correlation of basal line clinical parameter with residual ridge reduction. The results were significant for both the groups (group with graft and the control group).

Table 3

Clinical Parameters at 14th week

Parameter	Duration of time	Median (IQR)		P
		With the graft	Control group
Buccal gingiva thickness	Basal line	0.3 (0.3-0.5)	0.4 (0.4-0.5)	0.5
	14 week	1.4 (1-2)	1.4 (1-2)	>0.88
	Change test: Change=0	1.2 (0.8-1.5)	1.1 (0.6-1.9)	0.68
Lingual gingiva thickness	Basal line	0.7 (0.5-1.0)	0.7 (0.5-1.1)	>0.88
	14 weeks	2.0 (2.0-2.0)	2.0 (1.5-2.5)	>0.88
	Change=0	0.9 (0.9-1.5)	1.1 (0.7-1.5)	0.62
Apico-coronal span of keratinized mucosa	Basal line	3.98	4.12	0.32
	Week 14	4.12 (0.28)	3.58 (0.27)	0.30
	-	-0.12 (95% CI: (-0.64-0.41)	-0.13 (95% CI: (-0.65-0.39)	0.989

CI: Confidence interval, IQR: Interquartile range

Table 4

B-L plates (radiographic assessment of the height)

Parameter	Duration	>Median (IQR)		Control and graft comparison (P)
		Graft group	Control group
Facial plate height	Basal line	2.33 (0.93-3.50)	3.03 (1.98-3.73)	0.595
	14 weeks	3.38 (2.56-4.50)	4.20 (3.26-6.28)	0.094
	Change Test: change=0	0.61 (0.46-0.94)	1.17 (0.70-2.10)	0.012
Wilcoxon signed-rank (P)		<0.0001	<0.0001
Lingual plate height	Basal line	1.82 (1.25-2.33)	1.40 (0.93-3.03)	>0.99
	14 weeks	2.80 (1.70-3.02)	2.80 (1.86-3.70)	0.535
	-	0.47 (0.23-0.89)	0.70 (0.46-1.40)	0.065
		P<0.0001	P<0.0001

IQR: Interquartile range

Table 5

Correlation between ridge loss parameters at basal line

Parameter	Both groups (slope)
	Slope	95% CI	P
Thickness of bone plate
Buccally	8.97	12.02-7.33	<0.0001
Lingually	-0.09	-4.39-2.99	0.897
Gingival thickness
Buccally	-2.11	-9.16-8.24	0.698
Lingually	1.04	-3.26-5.19	0.597
Keratinized gingiva span
Buccally	-0.45	-2.54-0.99	0.402

CI: Confidence interval

DISCUSSION

The present clinical study was carried out to if the technique of the socket grafting can reduce the alveolar bone resorption postextraction radiographically and clinically. Furthermore, if postgraft placement the changes in radiographic and clinical measurements are affected by the span of buccal plate. However, other authors showed that nonresorbable membrane use can lead to unpredictable outcomes added with the complications.[8]

In the recent literature, there documented the foreseeable results can be obtained with the scaffold membranes use with very low incidence of complications. Achieving these results greatly depends on the adequate selection of patients and proper supervision postoperatively as to minimize the complications.[9] Recently, newer techniques have been reinforced in the socket shielding techniques, including the use of free gingival grafts, incorporation of bone grafts, and collagen plug infusion. All these graft materials have depicted favorable results yielding.[10] With all these favorable and supporting studies, betatricalcium phosphate membrane was chosen for the present study, and this membrane use showed no postoperative complication in any of the patients of the two study groups.

Usually, resorption and healing of β-TCP particles are expected in 3–6 months after its placement as evident in literature.[11] Most of the β-TCP gets biodegraded by both osteoclastic activities and/or chemical dissolution of the molecule in the calcium and phosphate components followed by replacement with healthy bone.[101112]

Literature has provided evidence in support to the fact that ridge preservation procedures reduce the bone dimensional changes compared with the extraction without ridge preservation procedures.[12] However, as per a systemic review, although, there are various evidences which depicts that there exists the preservation of alveolar ridge, complete obliteration of bone resorption (horizontal and vertical) postextraction cannot be avoided completely.[13] The results of this study are in accordance with these findings as there was some loss of ridge span and height in both the experimental groups even after performing ridge preservation technique. Thus, ridge preservation procedures do not result in complete dimensional stability but are designed to reduce the loss of ridge dimension compared to sites left to heal naturally after tooth extraction.

Murata reported the first clinical case of sinus augmentation using auto-dentin as a bone graft material. Interestingly, dentin and bone are almost similar with respect to composition. They consist of body fluid (10%), collagen (18%), noncollagenous proteins (2%), and hydroxyapatite (HA) (70%) in weight volume. According to Urist in 1965, demineralized dentin matrix and demineralized bone matrix contain mainly type-I collagen with growth factors such as bone morphogenetic proteins 2 and fibroblast growth factors. These bioactive molecules are thought to contribute to osteoinduction and osteoconductive property of human tooth as a graft material.[1314] Mineral content wise, tooth consists of low -crystalline HA and possibly other calcium phosphate minerals such as β-TCP, amorphous calcium phosphate, and octacalcium phosphate which is quite similar to human bone tissues.[14]

CONCLUSIONS

This study reveals that alveolar ridge preservation for socket grafting provides an additional effect by maintaining the integrity of bone volume. This leads no further grafting at the implant site. This study evaluate that if the bone density of the buccal plate is <1 mm, then ridge preservation is not done while if it is >10% alveolar ridge reduction seen postextraction, it suggests that in future this reduction will continue with the thinning of the buccal cortical plate.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.